... About ATNF overview . ... Parkes | ... Pulse profiles obtained from GX 1+4 can be broadly classified into two classes which have generally been found during the two distinct eras - the 1970's high intensity spin-up era and the later low intensity, principally spin-down, era. ... At higher energies the profile is generally simpler and the phase of deepest minimum corresponds to that of the low energy 'dip' (Doty et al. ... Other significant features are sometimes observed in the GX 1+4 pulse profiles...